Electrical detecting-machine



E. L. WELCH. ELECTRICAL DETECTING MACHINE.

APPLICAHON FILED JAN 19, I918.

Patented J une 8, 1920.

2 SHEETSSHEET 1- E. L. WELCH. I ELECTRICAL DETECTING MACHINE.

APPLICAHON FILED JAN-19,1918.

Patented June' 8, 1920.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

EMERY L. VVELCI-I, 'OF LIMA, OHIO.

ELECTRICAL DETEGTING-lvL-f-XCHINE.

To all whom it may concern Be it known that I, Erznnv L. lVnLoII, a citizen of the United States of America, residing at Lima, in the county of Allen and Stateo'f Ohio, have invented certain new and useful Improvements in Electrical Detecting-Machines, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to a signaling device used in connection with telephones.

An object of my invention is the provision of simple and efiicient means to prevent unauthorized interruption of a conversation between two parties on a telephone exchange by another party listening to the conversation without proper authority to do so.

Other objects and advantages of my device will be more fully appreciated upon reading the following specification.

in the drawings: 7

Figure l is a diagrammatic view of a part or" a telephone system, showing my device connected up with the system.

Fig. 2 is a fragmentary view of a tele phone box, showing my device in position therein and connected to the hook of a telephone, the door of the box being open.

Fig. 3 is a view in side elevation of my signaling device, showing one of the sides thereof removed, the core in section, and a fragmentary view of the hook in position upon the device.

Fi i is a transverse sectional view of one or the devices constructed in accordance with my invention, while Fig. 5 is a view in side elevation looking at the opposite side of the device from that shown in Fig. 3.

Fig. 6 is a view in side elevation of a modined form of my device.

Referring to the drawings by reference characters and numerals, A designates the party line, and B and C are ordinary telephone boxes in circuit with each other through the party line A, and D is the third telephone connected up on the party line A, the telephone D being shown in diagram, and is of an ordinary structure known to the art. I are showing these three telephones connected in series to better illustrate the application of my device.

My detecting device comprises a base 1 and a standard 2. The standard 2 at its upper end is cylindrical in shape and in the Specification of Letters Patent.

Application filed January 19, 1918.

lihttented June 8, 1920.

Serial No. 212,646.

inner face or" this hollow, cylindrical portion 301 thestandard are long pieces of insulation l and short pieces of insulation 5, so that long and short sounds will be produced as hereinafter explained. On one side oi the cylindrical portion 3 or" the standard 2 are pins 6 that extend through an insulating disk or cover 7 for holding the disk or cover against the side of the cylinder 3; On opposite side of the cylinder 3 is also an insulating cover 8.

A rotatable hub 9 is provided with a stub shaft 10 that is pointed at 11, and on the opposite side 01 the hub 9 there is also formed a stub shaft 12 that has threaded extension 13. The threaded extension 13 is threaded into a disk 1% whereby, when the disk is rotated, rotary movement will be imparted to the hub 9.

The pointed end 11 of the stub shaft 10 bears against spring contact finger 15 that is secured to the side 7 through the medium of the screw 16, which screw also holds a wire 17 upon the side 7 for the purpose hereinafter specified.

The hub 9 is provided with recess in wl ich the slidable contact pin 18 is positioned, this contact pin being pointed at its outer end for facilitating the engagement of the long and short metal portions between the similar insulated portions 4 and 5 of the inner face of the cylinder 3, the pin 18 being always in an extended position by reason of the coiled spring 19 bearing against he inner end thereof, Figs. 3 and Current enters the device through the wire 20 and thence through the metal portion between the insulations el and 5, through pin 18, hub 9 and thence through point 11,1inger 15 and through wire 1 on through telephone and out on opposite side of telephone line. This accomplished by separating he one battery wire, shown in Fig. 1. connecting these ends of wires to the net tive post of detector 20 opposite end to positive post 15, which will be clearly seen closes the battery circuit as the pin 18 comes in contact with meta portions of cylinders 8 which causes breaks or sounds of shorts and longs to be distinctly heard by l aarties on the line as herein specified.

The ordinary telephone hook 21, for holding the receiver, is surro ded by a twopiece clamp 22. Said clamp 22 comprises a primary angular section 23 and an auxiliary angular section 24:, each section termi i by screw 25. A second pair of lips, as at 26,

is also held together by medium of a fastening device 27, which device '27 also extends through the upper part of a connecting link '28, the connecting link 28 being pivotally connected by screw 29 to the disk 14 which disk 14 is fixed as hereinbefore described to the hub 9.

When the receiver is lifted ofi" hook 21 the spring member 30, Figs. 1 and 2, will cause the hook to rise thereby drawing on the link 28 and rotating the disk 14 and the hub 9' attached. thereto, causing the spring pressed contact 18, in the hub, to ride over the metal and insulated surfaces of the cylindrical portion 3, causing long and short vibrations or sounds to travel over the party line, and readily indicating to two users of two phones that some one has deliberately lifted a receiver and is listening to the conversation on the line.

All that is required to connect my device to any telephone is suificient battery force, either dry cells, storage battery or direct electric current.

' In Fig. 6 I have shown a modified form of my device in which the hook 21 engages a roller 32 carried on pin 83, which pin 33 is fixed to the disk 14. A weight 34 is fastened as at 35, to the disk 14 so that when the receiver is lifted from the hook 21, the weight will cause the disk 14 to rotate, producing the same effect as with the clamp 22 and the link 28. In F ig..6 the position of the device is that when the receiver is off the hook; when the receiver is on the hook 21 the hook travelsslightly downward, causing the weight 34 to be positioned closer to the hook 21, so that when the receiver is lifted off the hook the disk will rotate through rotating disk 14 a series of slight scratching sounds of shorts and longs will be heard in all of the used instruments, thereby inclicating to all of the parties on the same line that another person is listening, thereby warning the first parties of the line that an eavesdropper is listening to the conversation.

It will be obvious that certain alterations and modifications can be made without departing from the spirit and scope of this invention, such alterations and modifications falling within the scope of the appended claims.

What I claim is:

1. A device of the class described, com prising a standard provided at its upper end with a cylindrical portion, said cylindrical portion provided on its inner face with a plurality of long and short insulations and long and short metal surfaces, a rotary hub in said cylindrical portion, a spring pressed pin in said hub and being adapted to engage said insulated and uninsulated portions of the cylindrical portion, a telephone receiver hook, and means connecting said telephone receiver hook and said hub portion whereby when thehook is moved movement will be. imparted to the hub thereby causing the contact pin to ride over the insulated and uninsulated surfaces of the cylindrical portion.

2. A detecting device, comprising a standard, means carried by said standard. for causing a series of sounds to be transmitted over a telephone line, a hook clamp comprising a plurality of sections, means deetachably holding said sections together, and

means pivotally connecting said hook clamp to said sound transmitting means carried by the standard.

3. In a device of the class described, the combination with sound transmitting means, of' a hook clamp positioned contiguous to said sound transmitting means, said hook clamp comprising angular sections, means detachably securing said sections together, and a link pivotally connected to one end of said hook clamp and at its opposite end to said sound transmitting means.

In testimony whereof I hereunto affix my signature.-

EMERY L. WELGH. 

